Krism:
It doesn't really bother me as long as it's in keeping with the restaurants level of formality, so I wouldn't mind this in your standard family dining place. I once had a waitress sit down in the booth with us while taking our order :o

ladyknight1:
Wouldn't bother me at all as long as they did their job properly.

Yvaine:
It irks me, but I know it's a thing. I've also experienced the "server sitting in your booth" thing. At the restaurants that do this gimmick, everybody does it, so I think it's a rule set by the employer in most cases. The waitress in the story was unprofessional, but she was unprofessional because she was wasted out of her gourd, not because she knelt. She was probably required or strongly encouraged to kneel.

I agree with Pioneer, it sounds like getting up and down all the time would be even more strain on the server's legs and feet than just remaining standing would be, though if any servers chime in and say that it hurts less to do that, I'll rethink the whole thing. Servers already have to deal with enough pain and I'm all for reducing it.

Coley:
I put this in the category of servers sitting with the customers. It makes me uncomfortable, and I don't like it. If I see all the servers in a restaurant doing that or a similar variation, then I figure the management is requiring it. Otherwise, it comes across to me as a quirk with one server. It feels too familiar. The sitting-with-the-customers thing bothers me more than the kneeling though.

Hmmmmm:
The only time I've had this happen was in casual restaurants that were loud (sports focused with lots of TVs on) and the server was doing it so neither he nor our table needed to shout. It didn't bother me. I'd find it odd in other situations. I also remember a waitress doing it when my DD was young and learning to place her own order and she kneeled down to table level to interact with DD.